Why do we call the equilibrium that exists between a liquid and its vapor in a closed container a dynamic equilibrium?
Its dynamic because there will be liquid boiling off and changing into vapour while at the same time, there will be vapour particles condensing and reentering the liquid phase.
The equilibrium which exists between a liquid and its vapour is called the dynamic equilibrium. This exists when the vapour pressure remains constant. Two opposing processes (such as evaporation and condensation) that occur at the same rate and thus produce no net change in a system constitute a dynamic equilibrium.The number of molecules of a liquid becoming vapour will be equal to the number of molecules condensing into liquid in a closed container. The rate of evaporation of liquid water is equal to the rate of condensation of water vapour. The liquid phase is in equilibrium with its own vapour phase. The melting point of a solid is the same as the freezing point of the liquid. At that temperature, the solid and liquid states of the substance are in equilibrium. For water, this equilibrium occurs at 0oC. Vapour-liquid Equilibrium is when both the liquid and vapour phases of a substance are in Equilibrium. This state is achieved when the partial pressure of the vapour phase is equal to the saturation vapour pressure of the liquid phase at the given temperature. At the eutectic point, the liquid phase is in equilibrium with the two solid phases. Since their compositions are the same, no separation is possible at the eutectic point. The corresponding eutectic temperature represents the minimum freezing (or melting) temperature of the mixture. In a closed container, there is dynamic equilibrium between the vapour phase, and the liquid phase, and the rate of evaporation is equal to the rate of condensation. In a closed container, as in the example below, these processes continuously occur. This is called dynamic equilibrium. In dynamic equilibrium, reactions continue to proceed in the forward and reverse direction; however, there is no net change in the amount of product or starting material. Dynamic equilibrium in terms of the vapor pressure of a liquid is a point at which the rate of evaporation is equal to the rate of condensation. At this point, there is no net change in the system. Even when the system is in equilibrium, there is still some molecular movement, but the net motion, on average, is zero. This is called dynamic equilibrium. The situation is "equilibrium" in that the observable properties of the liquid and gas in the container are not changing, but the situation is "dynamic" in that there is constant movement of molecules between phases.
We call the equilibrium that exists between a liquid and its vapor in a closed container a dynamic equilibrium because the liquid and vapor are constantly interconverting. Even though the amount of liquid and vapor remains constant, individual molecules are constantly moving between the two phases.
On the molecular level, the liquid molecules are constantly evaporating into the vapor phase. This occurs because some of the molecules at the surface of the liquid have enough energy to overcome the intermolecular forces that are holding them together. Once in the vapor phase, the molecules are still moving around, but they are also colliding with each other and with the walls of the container. Some of these collisions will have enough energy to cause the molecules to condense back into the liquid phase.
The rate at which molecules evaporate and condense is constantly changing, but it always reaches a point where the two rates are equal. This is the point of equilibrium. At equilibrium, the amount of liquid and vapor remains constant, but the individual molecules are still constantly moving between the two phases.
This is different from a static equilibrium, where there is no movement or change. In a dynamic equilibrium, there is constant movement and change, but the overall system remains the same.
The equilibrium vapor pressure of a liquid is the pressure exerted by the vapor in equilibrium with the liquid in a closed container. The equilibrium vapor pressure depends on the temperature of the liquid and the intermolecular forces between the liquid molecules. As the temperature increases, the equilibrium vapor pressure increases. This is because the molecules have more energy at higher temperatures, so they are more likely to evaporate.
The intermolecular forces between the liquid molecules also affect the equilibrium vapor pressure. Stronger intermolecular forces will hold the liquid molecules together more tightly, making it more difficult for them to evaporate. Therefore, liquids with stronger intermolecular forces will have lower equilibrium vapor pressures than liquids with weaker intermolecular forces.
No: equilibrium cannot be achieved between water and its vapours in an open vessel. Since water vapours are escaping out of the container, to take their place more of liquid water changes to vapours. In the case of a liquid enclosed in a chamber, the molecules continuously evaporate and condense, but the amounts of liquid and vapor do not change with time. The pressure exerted by a vapor in dynamic equilibrium with a liquid is the equilibrium vapor pressure of the liquid. This process continuous till the entire water has changed to the vapours. To exist a dynamic equilibrium between a liquid and its vapour, the rate of evaporation of liquid should be equal to the rate of condensation of vapour. Because the processes of evaporation and condensation are occurring at the same rate, there is a dynamic equilibrium between the vapor and the liquid, which results in a constant vapor pressure. The temperature at which the solid and liquid forms of a pure substance can exist in equilibrium is called melting point. It can be also defined as the temperature at which a solid becomes a liquid at normal atmospheric pressure. Yes all chemical equilibrium takes place in a closed container. Chemical equilibrium is a static equilibrium and is a reversible one. At the eutectic point, the liquid phase is in equilibrium with the two solid phases. Since their compositions are the same, no separation is possible at the eutectic point. The corresponding eutectic temperature represents the minimum freezing temperature of the mixture. The system must be closed, meaning no substances can enter or leave the system. Equilibrium is a dynamic process. Even though we don't necessarily see the reactions, both forward and reverse are taking place. The rates of the forward and reverse reactions must be equal.
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